subroutine F77_openfiles(pdb,xtc,n)
    implicit none
    character(len=140) :: pdb,xtc
    integer :: n
    interface
        subroutine F_openfiles(pdb,xtc,n)
            implicit none
            character(len=140) :: pdb,xtc
            integer :: n
        end subroutine F_openfiles
    end interface
    call F_openfiles(pdb,xtc,n);
end subroutine F77_openfiles
